A polyphenylene ether-based resin composition (hereinafter, also referred to as “m-PPE resin composition”) based on a polyphenylene ether (hereinafter, also referred to as “PPE”)-based resin has improved molding processability and a predetermined heat resistance, is also excellent in electrical properties, dimensional stability, impact resistance, acid resistance and alkali resistance, and is low in water-absorbing property and specific gravity. In addition, since the m-PPE resin composition can achieve flame retardancy using no harmful halogen-based compound and antimony compound, it is also excellent in terms of environment as well as health and safety. Therefore, such an m-PPE resin composition is widely utilized in applications such as various electric/electronic parts, office equipment parts, automobile parts, building materials, various other exterior materials, and industrial goods.
Patent Document 1 discloses a polymer mixture using a hydrogenated styrene-butadiene-styrene block copolymer and no polystyrene.
Patent Document 2 discloses a composition containing a hydrogenated styrene-butadiene-styrene block copolymer having a specified circle-equivalent average particle diameter.
Patent Document 3 discloses a flame-retardant composition using a hydrogenated styrene-butadiene-styrene block copolymer having a molecular weight of 200,000 atomic mass units to 400,000 atomic mass units.
Patent Document 4 discloses a production method in which, when a flame-retardant composition including a hydrogenated styrene-butadiene-styrene block copolymer having a number average molecular weight of 150,000 to 350,000 is molten and kneaded using an extruder, the range from the upstream side of the extruder to 45 to 75% of the extruder length is defined as a non-melting and mixing zone, and a melting and kneading zone having 5 to 30% of the extruder length is provided downstream of the non-melting and mixing zone.
Patent Document 5 discloses a method for producing a resin composition using a polyphenylene ether powder, wherein a specified powder-supply facility location and specified extruding conditions are adopted.